code: def df_hist():
      np.random.seed(42)
  
      df_hist = pd.DataFrame(
          {
              "a": np.random.randn(1000) + 1,
              "b": np.random.randn(1000),
              "c": np.random.randn(1000) - 1,
          },
          columns=["a", "b", "c"],
      )
  
      return df_hist
  
imports: import os
  import numpy
  import pandas
  import pytest
  import pandas_bokeh
label_desc: Use image node_id 4 for calling a global function with example usage: df_hist() and returns: df_hist